Cervix &a Back pain

Cece • • мαмα σf 3 •
So I'm 31 weeks tomorrow and ever since a couple days ago I started getting shooting pains in my cervix. I thought it was completely normal. Now just a little while ago I went to sit down and got a BAD throbbing pain in my lower back that lasted about 15 seconds.. should I ignore it unless it happens again or call my doctor in the morning? I have gestational diabetes and anterior placenta if that makes a difference.